1. Field of the Invention
The present invention relates to electrical, or insulated wire cables, of the type which have a plurality of terminal points along the length of the cable and are bent into precise selected forms to make connections with a plurality of electrical components in electronic or electromechanical devices, such as pinball machines, and methods and apparatus for assembling same.
2. Description of the Prior Art
Such precision electrical cables are used to make connections with numerous components located in a relatively small area of space around which the cable is routed. I am most familiar with the use of such cables to make connections on what is known as an "insert board" in a pinball machine but other applications exist. Such space limitations allow very little room for excess cable, and the location of the various bends and intermediate terminal points must be done precisely. Such cables are therefore referred to herein as precision cables.
The past method of assembling precision electrical cables that I know of has been to assemble them in their final bent form on an assembly device 10 of the type shown in FIGS. 1A and 1B which illustrate a cable assembly device for a cable to be utilized in a pinball machine.
Referring to FIG. 1A, an assembly device 10 comprises a flat board 11 placed on frame 13. A wiring pattern, or cable path 12, is designated on board 11 by a plurality of wire retainers 56 which may be nail-like members releasably mounted to and projecting from the board 11 at various points along pattern 12. A common starting point 14 is marked by one retainer 56. Other retainers 56 mark various breakout points 18 along cable path 16 and wire terminal points 15. Cable path 16 is in a generally square configuration, having three major bend points 17, 19 and 21 around which the cable path 16 is bent. During assembly, individual wire leads are broken out from the common cable path 16 at the breakout points 18 and terminate at terminal points 15. A paper pattern 54 corresponding to the wiring pattern 12 and containing wiring instructions may be held to board 11 by wire retainers 56.
Individual wires 24', such as 18 gauge insulated electrical wire, are hand drawn by an assembler from a wire supply board 20 as best seen in FIG. 1B. Individual wires 24' from spools 24 are drawn through holes 22 in board 20. Often a group or set of wires are drawn from wire supply board 20 and secured to the retainer 56 at starting point 14. Then, each individual wire 24' of the set is strung along cable path 16, around its respective breakout point 18 and secured at its respective terminal, or termination point 15. Several wires may share the same termination point 15.
After the first set of wires has been assembled, each individual wire 24' is cut at its terminal and the assembler ties them together and drops them back to supply board 20. Wires 24' knotted at 23 are shown in position for subsequent use on the next cable pattern to be assembled. Another set of wires is then drawn from supply board 20 and secured at starting point 14. Each individual wire is then strung along path 16, bent around its breakout point 18 and terminated at its respective termination point 15. This second set of wires, after assembly, is then tied to keep them together and dropped back to supply board 20. Each succeeding set of wires is likewise handled until all of the wires have been secured in place. Such precision cables may have on the order of twenty individual wires and terminals.
Once all the wires are assembled on the assembly device 10, they are bound together at various points along common cable path 16. Binding is generally accomplished by the use of a manually actuated "tie-gun". The tie-gun secures the individual wires of the cable together with a plastic strap. Other tie-guns are available, but some tie-guns tend to be large and unwieldy when used along the vertical lengths of cable. Once tied, the cable is removed from assembly device 10 and, but for the addition of connectors, is ready for use.
It should be noted that only after each individual cable has been completed is a subsequent cable then started. Each step performed for the prior cable must be repeated again, start to finish, for the next succeeding cable.